This invention relates to imidazoquinoline compounds that have ether and amido functionality at the 1-position, and to pharmaceutical compositions containing such compounds. A further aspect of this invention relates to the use of these compounds as immunomodulators, for inducing cytokine biosynthesis in animals, and in the treatment of diseases, including viral and neoplastic diseases.
The first reliable report on the 1H-imidazo[4,5-c]quinoline ring system, Backman et al., J. Org. Chem. 15, 1278-1284 (1950) describes the synthesis of 1-(6-methoxy-8-quinolinyl)-2-methyl-1H-imidazo[4,5-c]quinoline for possible use as an antimalarial agent. Subsequently, syntheses of various substituted 1H-imidazo[4,5-c]quinolines were reported. For example, Jain et al., J. Med. Chem. 11, pp. 87-92 (1968), synthesized the compound 1-[2-(4-piperidyl)ethyl]-1H-imidazo[4,5-c]quinoline as a possible anticonvulsant and cardiovascular agent. Also, Baranov et al., Chem. Abs. 85, 94362 (1976), have reported several 2-oxoimidazo[4,5-c]quinolines, and Berenyi et al., J. Heterocyclic Chem. 18, 1537-1540 (1981), have reported certain 2-oxoimidazo[4,5-c]quinolines.
Certain 1H-imidazo[4,5-c]quinolin-4-amines and 1- and 2-substituted derivatives thereof were later found to be useful as antiviral agents, bronchodilators and immunomodulators. These are described in, inter alia, U.S. Pat. Nos. 4,689,338; 4,698,348; 4,929,624; 5,037,986; 5,268,376; 5,346,905; and 5,389,640, all of which are incorporated herein by reference.
There continues to be interest in the imidazoquinoline ring system.
Certain 1H-imidazo[4,5-c]naphthyridine-4-amines, 1H-imidazo[4,5-c]pyridin-4-amines, and 1H-imidazo[4,5-c]quinolin-4-amines having an ether containing substituent at the 1 position are known. These are described in U.S. Pat. Nos. 5,268,376; 5,389,640; 5,494,916; and WO 99/29693.
Despite these attempts to identify compounds that are useful as immune response modifiers, there is a continuing need for compounds that have the ability to modulate the immune response, by induction of cytokine biosynthesis or other mechanisms.
We have found a new class of compounds that are useful in inducing cytokine biosynthesis in animals. Accordingly, this invention provides imidazo[4,5-c]quinoline-4-amine and tetrahydroimidazo[4, 5-c]quinoline-4-amine compounds that have an ether containing substituent at the 1-position. The compounds are defined by Formulas (I) and (II), which are defined in more detail infra. These compounds share the general structural formula: 
wherein X, R1, R2, and R are as defined herein for each class of compounds having Formulas (I) and (II).
The compounds of Formulas (I) and (II) are useful as immune response modifiers due to their ability to induce cytokine biosynthesis and otherwise modulate the immune response when administered to animals. This makes the compounds useful in the treatment of a variety of conditions such as viral diseases and tumors that are responsive to such changes in the immune response.
The invention further provides pharmaceutical compositions containing the immune response modifying compounds, and methods of inducing cytokine biosynthesis in an animal, treating a viral infection in an animal, and/or treating a neoplastic disease in an animal by administering a compound of Formula (I) or (II) to the animal.
In addition, the invention provides methods of synthesizing the compounds of the invention and novel intermediates useful in the synthesis of these compounds.
As mentioned earlier, we have found certain compounds that induce cytokine biosynthesis and modify the immune response in animals. Such compounds are represented by Formulas (I) and (II) as shown below.
Imidazoquinoline compounds of the invention, which have ether and amide functionality at the 1-position, are represented by Formula (I): 
wherein:
X is xe2x80x94CHR5xe2x80x94, xe2x80x94CHR5-alkyl-, or xe2x80x94CHR5-alkenyl-;
R1 is selected from the group consisting of:
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heterocyclyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94H;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkenyl;
R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94NR7CR3xe2x80x94R6-heterocyclyl; and
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R8;
each Z is independently xe2x80x94NR5xe2x80x94, xe2x80x94Oxe2x80x94, or xe2x80x94Sxe2x80x94;
R2 is selected from the group consisting of:
-hydrogen;
-alkyl;
-alkenyl;
-aryl;
-heteroaryl;
-heterocyclyl;
-alkyl-Y-alkyl;
-alkyl-Y-alkenyl;
-alkyl-Y-aryl; and
-alkyl or alkenyl substituted by one or more substituents selected from the group consisting of:
xe2x80x94OH;
-halogen;
xe2x80x94N(R5)2;
xe2x80x94COxe2x80x94N(R5)2;
xe2x80x94COxe2x80x94C1-10 alkyl;
xe2x80x94COxe2x80x94Oxe2x80x94C1-10 alkyl;
xe2x80x94N3;
-aryl;
-heteroaryl;
-heterocyclyl;
xe2x80x94CO-aryl; and
xe2x80x94CO-heteroaryl;
each R3 is xe2x95x90O or xe2x95x90S;
each R4 is independently alkyl or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
each R5 is independently H or C1-10 alkyl;
R6 is a bond, alkyl, or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
R7 is H, C1-10 alkyl, or arylalkyl; or R4 and R7 can join together to form a ring;
R8 is H or C1-10 alkyl; or R7 and R8 can join together to form a ring;
each Y is independently xe2x80x94Oxe2x80x94 or xe2x80x94S(O)0-2xe2x80x94;
n is 0 to 4; and
each R present is independently selected from the group consisting of C1-10 alkyl, C1-10 alkoxy, hydroxy, halogen and trifluoromethyl;
or a pharmaceutically acceptable salt thereof.
The invention also includes tetrahydroimidazoquinoline compounds that bear an ether and amide containing substituent at the 1-position. Such tetrahydroimidazoquinoline compounds are represented by Formula (II): 
wherein:
X is xe2x80x94CHR5xe2x80x94, xe2x80x94CHR5-alkyl-, or xe2x80x94CHR5-alkenyl-;
R1 is selected from the group consisting of:
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94R3xe2x80x94Zxe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heterocyclyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94H;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heterocyclyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R8;
each Z is independently xe2x80x94NR5xe2x80x94, xe2x80x94Oxe2x80x94, or xe2x80x94Sxe2x80x94;
R2 is selected from the group consisting of:
-hydrogen;
-alkyl;
-alkenyl;
-aryl;
-heteroaryl;
-heterocyclyl;
-alkyl-Y-alkyl;
-alkyl-Y-alkenyl;
-alkyl-Y-aryl; and
-alkyl or alkenyl substituted by one or more substituents selected from the group consisting of:
xe2x80x94OH;
-halogen;
xe2x80x94N(R5)2;
xe2x80x94COxe2x80x94N(R5)2;
xe2x80x94COxe2x80x94C1-10 alkyl;
xe2x80x94COxe2x80x94C1-10 alkyl;
xe2x80x94N3;
-aryl;
-heteroaryl;
-heterocyclyl;
xe2x80x94CO-aryl; and
xe2x80x94CO-heteroaryl;
each R3 is xe2x95x90O or xe2x95x90S;
each R4 is independently alkyl or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
each R5 is independently H or C1-10 alkyl;
R6 is a bond, alkyl, or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
R7 is H, C1-10 alkyl, or arylalkyl; or R4 and R7 can join together to form a ring;
R8 is H or C1-10 alkyl; or R7 and R8 can join together to form a ring;
each Y is independently xe2x80x94Oxe2x80x94 or xe2x80x94S(O)0-2xe2x80x94;
n is 0 to 4; and
each R present is independently selected from the group consisting of C1-10 alkyl, C1-10 alkoxy, hydroxy, halogen, and trifluoromethyl;
or a pharmaceutically acceptable salt thereof.
Preparation of the Compounds
Compounds of the invention can be prepared according to Reaction Scheme I where R, R2, R3, R4, X, Z and n are as defined above and R11 is xe2x80x94R6-alkyl, xe2x80x94R6-aryl, xe2x80x94R6-heteroaryl or xe2x80x94R6-heterocyclyl where R6 is as defined above.
In step (1) of Reaction Scheme I a 1H-imidazo[4,5-c]quinolin-1-yl alcohol of Formula X is alkylated with a halide of Formula XI to provide a 1H-imidazo[4,5-c]quinolin-1-yl ether of Formula XII. The alcohol of Formula X is reacted with sodium hydride in a suitable solvent such as N,N-dimethylformamide to form an alkoxide. Alternatively, the alkoxide can be formed by adding the alcohol to a biphasic mixture of aqueous 50% sodium hydroxide and an inert solvent such as dichloromethane in the presence of a phase transfer catalyst such as benzyltrimethylammonium chloride. The alkoxide is then combined with the halide. The reaction can be carried out at ambient temperature. Many compounds of Formula X are known, see for example, Gerster, U.S. Pat. No. 4,689,338; others can readily be prepared using known synthetic routes, see for example, Gerster et al., U.S. Pat. No. 5,605,899 and Gerster, U.S. Pat. No. 5,175,296. Many halides of Formula XI are commercially available; others can be readily prepared using known synthetic routes.
In step (2) of Reaction Scheme I a 1H-imidazo[4,5-c]quinolin-1-yl ether of Formula XII is oxidized to provide a 1H-imidazo[4,5-c]quinoline-5N-oxide of Formula XIII using a conventional oxidizing agent capable of forming N-oxides. Preferably a solution of a compound of Formula XII in chloroform is oxidized using 3-chloroperoxybenzoic acid at ambient temperature.
In step (3) of Reaction Scheme I a 1H-imidazo[4,5-c]quinoline-5N-oxide of Formula XIII is aminated to provide a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XIV which is a subgenus of Formula I. Step (3) involves (i) reacting a compound of Formula XIII with an acylating agent and then (ii) reacting the product with an aminating agent. Part (i) of step (3) involves reacting an N-oxide of Formula XIII with an acylating agent. Suitable acylating agents include alkyl- or arylsulfonyl chlorides (e.g., benezenesulfonyl chloride, methanesulfonyl chloride, p-toluenesulfonyl chloride). Arylsulfonyl chlorides are preferred. Para-toluenesulfonyl chloride is most preferred. Part (ii) of step (3) involves reacting the product of part (i) with an excess of an aminating agent. Suitable aminating agents include ammonia (e.g., in the form of ammonium hydroxide) and ammonium salts (e.g., ammonium carbonate, ammonium bicarbonate, ammonium phosphate). Ammonium hydroxide is preferred. The reaction is preferably carried out by dissolving the N-oxide of Formula XIII in an inert solvent such as dichloromethane, adding the aminating agent to the solution, and then slowly adding the acylating agent. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods.
Alternatively, step (3) may be carried out by (i) reacting an N-oxide of Formula XIII with an isocyanate and then (ii) hydrolyzing the resulting product. Part (i) involves reacting the N-oxide with an isocyanate wherein the isocyanato group is bonded to a carbonyl group. Preferred isocyanates include trichloroacetyl isocyanate and aroyl isocyanates such as benzoyl isocyanate. The reaction of the isocyanate with the N-oxide is carried out under substantially anhydrous conditions by adding the isocyanate to a solution of the N-oxide in an inert solvent such as chloroform or dichloromethane. Part (ii) involves hydrolysis of the product from part (i). The hydrolysis can be carried out by conventional methods such as heating in the presence of water or a lower alkanol optionally in the presence of a catalyst such as an alkali metal hydroxide or lower alkoxide. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods. 
Compounds of the invention can be prepared according to Reaction Scheme II where R, R2, R4, R7, R11, X and n are as defined above and BOC is tert-butoxycarbonyl.
In step (1) of Reaction Scheme II the amino group of an aminoalcohol of Formula XV is protected with a tert-butoxycarbonyl group. A solution of the aminoalcohol in tetrahydrofuran is treated with di-tert-butyl dicarbonate in the presence of a base such as sodium hydroxide. Many aminoalcohols of Formula XV are commercially available; others can be prepared using known synthetic methods.
In step (2) of Reaction Scheme II a protected aminoalcohol of Formula XVI is converted to an iodide of Formula XVII. Iodine is added to a solution of triphenylphosphine and imidazole in dichloromethane; then a solution of a protected aminoalcohol of Formula XVI in dichloromethane is added. The reaction is carried out at ambient temperature.
In step (3) of Reaction Scheme II a 1H-imidazo[4,5-c]quinolin-1-yl alcohol of Formula X is alkylated with an iodide of Formula XVII to provide a 1H-imidazo[4,5-c]quinolin-1-yl ether of Formula XVIII. The alcohol of Formula X is reacted with sodium hydride in a suitable solvent such as N,N-dimethylformamide to form an alkoxide. The iodide is added to the alkoxide solution at ambient temperature. After the addition is complete the reaction is stirred at an elevated temperature (xcx9c100xc2x0 C.).
In step (4) of Reaction Scheme II a 1H-imidazo[4,5-c]quinolin-1-yl ether of Formula XVIII is oxidized to provide a 1H-imidazo[4,5-c]quinoline-5N-oxide of Formula XIX using a conventional oxidizing agent capable of forming N-oxides. Preferably a solution of a compound of Formula XVIII in chloroform is oxidized using 3-chloroperoxybenzoic acid at ambient temperature.
In step (5) of Reaction Scheme II a 1H-imidazo[4,5-c]quinoline-5N-oxide of Formula XIX is aminated to provide a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XX. Step (5) involves (i) reacting a compound of Formula XIX with an acylating agent and then (ii) reacting the product with an aminating agent. Part (i) of step (5) involves reacting an N-oxide of Formula XIX with an acylating agent. Suitable acylating agents include alkyl- or arylsulfonyl chlorides (e.g., benezenesulfonyl chloride, methanesulfonyl chloride, p-toluenesulfonyl chloride). Arylsulfonyl chlorides are preferred. Para-toluenesulfonyl chloride is most preferred. Part (ii) of step (5) involves reacting the product of part (i) with an excess of an aminating agent. Suitable aminating agents include ammonia (e.g., in the form of ammonium hydroxide) and ammonium salts (e.g., ammonium carbonate, ammonium bicarbonate, ammonium phosphate). Ammonium hydroxide is preferred. The reaction is preferably carried out by dissolving the N-oxide of Formula XIX in an inert solvent such as dichloromethane or 1,2-dichloroethane with heating if necessary, adding the aminating agent to the solution, and then slowly adding the acylating agent. Optionally the reaction can be carried out in a sealed pressure vessel at an elevated temperature (85-100xc2x0).
In step (6) of Reaction Scheme II the protecting group is removed by hydrolysis under acidic conditions to provide a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XXI. Preferably the compound of Formula XX is treated with hydrochloric acid/ethanol at ambient temperature or with gentle heating.
In step (7) of Reaction Scheme II a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XXI is converted to an amide of Formula XXII which is a subgenus of Formula I using conventional synthetic methods. For example, a compound of Formula XXI can be reacted with an acid chloride of Formula R11C(O)Cl. The reaction can be carried out by adding a solution of the acid chloride in a suitable solvent such as dichloromethane or 1-methyl-2-pyrrolidinone to a solution of a compound of Formula XXI at ambient temperature. Alternatively, a compound of Formula XXI can be reacted with an acid of Formula R11COOH. The reaction can be carried out at ambient temperature in a solvent such as dichloromethane or pyridine using a standard coupling reagent such as 1,3-dicyclohexylcarbodiimide or 1[3-(dimethylamino)propyl]-3-ethylcarbodiimide. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods. 
Compounds of the invention can be prepared according to Reaction Scheme III where R, R2, R4, R7, R11, X and n are as defined above and BOC is tert-butoxycarbonyl.
In step (1) of Reaction Scheme III the amino group of an aminoalcohol of Formula XXIII is protected with a tert-butoxycarbonyl group. A solution of the aminoalcohol in tetrahydrofuran is treated with di-tert-butyl dicarbonate in the presence of a base such as sodium hydroxide. Many aminoalcohols of Formula XXIII are commercially available; others can be prepared using known synthetic methods.
In step (2) of Reaction Scheme III a protected amino alcohol of Formula XXIV is converted to a methanesulfonate of Formula XXV. A solution of a compound of Formula XXIV in a suitable solvent such as dichloromethane is treated with methanesulfonyl chloride in the presence of a base such as triethylamine. The reaction can be carried out at a reduced temperature (0xc2x0).
In step (3a) of Reaction Scheme III a methanesulfonate of Formula XXV is converted to an azide of Formula XXVI. Sodium azide is added to a solution of a compound of Formula XXV in a suitable solvent such as N,N-dimethylformamide. The reaction can be carried out at an elevated temperature (80-100xc2x0 C.).
In step (3b) of Reaction Scheme III a compound of Formula XXVI is alkylated with a halide of Formula Hal-R7 to provide a compound of Formula XXVII. In compounds where R7 is hydrogen this step is omitted. The compound of Formula XXVI is reacted with sodium hydride in a suitable solvent such as N,N-dimethylformamide to form the anion and then combined with the halide. The reaction can be carried out at ambient temperature.
In step (4) of Reaction Scheme III an azide of Formula XXVI or XXVII is reduced to provide an amine of Formula XXVIII. Preferably, the reduction is carried out using a conventional heterogeneous hydrogenation catalyst such as palladium on carbon. The reaction can conveniently be carried out on a Parr apparatus in a suitable solvent such as methanol or isopropanol.
In step (5) of Reaction Scheme III a 4-chloro-3-nitroquinoline of Formula XXIX is reacted with an amine of Formula XXVIII to provide a 3-nitroquinoline of Formula XXX. The reaction can be carried out by adding an amine of Formula XXVIII to a solution of a compound of Formula XXIX in a suitable solvent such as dichloromethane in the presence of a base such as triethylamine. Many quinolines of Formula XXIX are known compounds or can be prepared using known synthetic methods, see for example, U.S. Pat. No. 4,689,338 and references cited therein.
In step (6) of Reaction Scheme III a 3-nitroquinoline of Formula XXX is reduced to provide a 3-aminoquinoline of Formula XXXI. Preferably, the reduction is carried out using a conventional heterogeneous hydrogenation catalyst such as platinum on carbon. The reaction can conveniently be carried out on a Parr apparatus in a suitable solvent such as toluene.
In step (7) of Reaction Scheme III a compound of Formula XXXI is reacted with a carboxylic acid or an equivalent thereof to provide a 1H-imidazo[4,5-c]quinoline of Formula XVIII. Suitable equivalents to carboxylic acid include orthoesters, and 1,1-dialkoxyalkyl alkanoates. The carboxylic acid or equivalent is selected such that it will provide the desired R2 substituent in a compound of Formula XVIII. For example, triethyl orthoformate will provide a compound where R2 is hydrogen and triethyl orthovalerate will provide a compound where R2 is butyl. The reaction can be run in the absence of solvent or in an inert solvent such as toluene. The reaction is run with sufficient heating to drive off any alcohol or water formed as a byproduct of the reaction. Optionally a catalyst such as pyridine hydrochloride can be included.
Alternatively, step (7) can be carried out by (i) reacting a compound of Formula XXXI with an acyl halide of Formula R2C(O)Cl or R2C(O)Br and then (ii) cyclizing. In part (i) the acyl halide is added to a solution of a compound of Formula XXXI in an inert solvent such as acetonitrile or dichloromethane. The reaction can be carried out at ambient temperature or at a reduced temperature. In part (ii) the product of part (i) is heated in an alcoholic solvent in the presence of a base. Preferably the product of part (i) is refluxed in ethanol in the presence of an excess of triethylamine or heated with methanolic ammonia.
Steps (8), (9), (10) and (11) are carried out in the same manner as steps (4), (5), (6) and (7) of Reaction Scheme II. 
Compounds of the invention can be prepared according to Reaction Scheme IV where R, R1, R2, X and n are as defined above In Reaction Scheme IV a 4-amino-1H-imidazo[4,5-c]quinolin-1-yl alcohol of Formula XXXII is alkylated with a halide of Formula XXXIII to provide a 1H-imidazo[4,5-c]quinolin-4-amine of Formula I. The alcohol of Formula XXXII is reacted with sodium hydride in a suitable solvent such as N,N-dimethylformamide to form an alkoxide. The halide is then added to the reaction mixture. The reaction can be carried out at ambient temperature or with gentle heating (xcx9c50xc2x0 C.) if desired. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods.
Many compounds of Formula XXXII are known, see for example Gerster, U.S. Pat. No. 4,689,338 and Gerster et. al., U.S. Pat. No. 5,605,899, the disclosures of which are incorporated by reference herein; others can readily be prepared using known synthetic routes, see for example, Andre et. al, U.S. Pat. No. 5,578,727; Gerster, U.S. Pat. No. 5,175,296; Nikolaides et al., U.S. Pat. No. 5,395,937; and Gerster et. al., U.S. Pat. No. 5,741,908, the disclosures of which are incorporated by reference herein. Many halides of Formula XXXIII are commercially available; others can be readily prepared using known synthetic methods. 
Compounds of the invention can be prepared according to Reaction Scheme V where R, R2, R4, R7, R11, X and n are as defined above.
In step (1) of Reaction Scheme V a 1H-imidazo[4,5-c]quinolin-4-amine of Formula XXI is reduced to provide a 6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine of Formula XXXIV. Preferably the reduction is carried out by suspending or dissolving a compound of Formula XXI in trifluoroacetic acid, adding a catalytic amount of platinum (IV) oxide, and then hydrogenating. The reaction can be conveniently carried out in a Parr apparatus.
Step (2) is carried out in the same manner as step (7) of Reaction Scheme II to provide a 6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine of Formula XXXV which is a subgenus of Formula II. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods. 
Compounds of the invention can be prepared according to Reaction Scheme VI where R, R1, R2, X and n are as defined above.
In Reaction Scheme VI a 4-amino-6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-1-yl alcohol of Formula XXXVI is alkylated with a halide of Formula XXXIII to provide a 6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolin-4-amine of Formula II. The alcohol of Formula XXXVI is reacted with sodium hydride in a suitable solvent such as N,N-dimethylformamide to form an alkoxide. The halide is then added to the reaction mixture. The reaction can be carried out at ambient temperature or with gentle heating (xcx9c50xc2x0 C.) if desired. The product or a pharmaceutically acceptable salt thereof can be isolated using conventional methods.
Many 6,7,8,9-tetrahydro-1H-imidazo[4,5-c]quinolines of Formula XXXVI are known, see for example, Nikolaides et al., U.S. Pat. No. 5,352,784; others can be prepared using known synthetic methods, see for example, Lindstrom, U.S. Pat. No. 5,693,811; the disclosures of which are incorporated by reference herein. 
The invention also provides novel compounds useful as intermediates in the synthesis of the compounds of Formulas (I) and (II). These intermediate compounds have the structural Formulas (III)-(V), described in more detail below.
One class of intermediate compounds has Formula (III): 
wherein:
X is xe2x80x94CHR5xe2x80x94, xe2x80x94CHR5-alkyl-, or xe2x80x94CHR5-alkenyl-;
R1 is selected from the group consisting of:
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-heterocyclyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94H;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94NR7CR3xe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heterocyclyl; and
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R8;
each Z is independently xe2x80x94NR5xe2x80x94, xe2x80x94Oxe2x80x94, or xe2x80x94Sxe2x80x94;
R2 is selected from the group consisting of:
-hydrogen;
-alkyl;
-alkenyl;
-aryl;
-heteroaryl;
-heterocyclyl;
-alkyl-Y-alkyl;
-alkyl-Y-alkenyl;
-alkyl-Y-aryl; and
-alkyl or alkenyl substituted by one or more substituents selected from the group consisting of:
xe2x80x94OH;
-halogen;
xe2x80x94N(R5)2;
xe2x80x94COxe2x80x94N(R5)2;
xe2x80x94COxe2x80x94C1-10 alkyl;
xe2x80x94COxe2x80x94Oxe2x80x94C1-10 alkyl;
xe2x80x94N3;
-aryl;
-heteroaryl;
-heterocyclyl;
xe2x80x94CO-aryl; and
xe2x80x94CO-heteroaryl;
each R3 is xe2x95x90O or xe2x95x90S;
each R4 is independently alkyl or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
each R5 is independently H or C1-10 alkyl;
R6 is a bond, or is alkyl, or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
R7 is H, C1-10 alkyl, or arylalkyl; or R4 and R7 can join to form a ring;
R8 is H or C1-10 alkyl; or R7 and R8 can join to form a ring;
each Y is independently xe2x80x94Oxe2x80x94 or xe2x80x94S(O)0-2xe2x80x94;
n is 0 to 4; and
each R present is independently selected from the group consisting of C1-10 alkyl, C1-10 alkoxy, hydroxy, halogen and trifluoromethyl; or a pharmaceutically acceptable salt thereof.
Another class of intermediates is described by formula (IV): 
wherein:
X is xe2x80x94CHR5xe2x80x94, xe2x80x94CHR5-alkyl-, or xe2x80x94CHR5-alkenyl-;
R1 is selected from the group consisting of:
xe2x80x94R4xe2x80x94CR3xe2x80x94Qxe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Qxe2x80x94R6-alkenyl;
Rxe2x80x94CR3xe2x80x94Qxe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Qxe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Qxe2x80x94R6-heterocyclyl;
xe2x80x94R4xe2x80x94CR3xe2x80x94Qxe2x80x94H;
xe2x80x94R4xe2x80x94NR5xe2x80x94CR3xe2x80x94R6-alkyl;
xe2x80x94R4xe2x80x94NR5xe2x80x94CR3xe2x80x94R6-alkenyl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-aryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heteroaryl;
xe2x80x94R4xe2x80x94NR7xe2x80x94CR3xe2x80x94R6-heterocyclyl; and
xe2x80x94Rxe2x80x94NR5xe2x80x94CR3xe2x80x94R8;
each Q is independently xe2x80x94NR5xe2x80x94 or xe2x80x94Oxe2x80x94;
each R3 is xe2x95x90O or xe2x95x90S;
each R4 is independently alkyl or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
each R5 is independently H or C1-10 alkyl;
R6 is a bond, alkyl, or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
R7 is H, C1-10 alkyl, or arylalkyl; or R4 and R7 can join to form a ring;
R8 is H or C1-10 alkyl; or R4 and R7 can join to form a ring;
n is 0 to 4; and
each R present is independently selected from the group consisting of C1-10 alkyl, C1-10 alkoxy, halogen and trifluoromethyl;
or a pharmaceutically acceptable salt thereof.
An additional class of intermediate compounds has the formula (V): 
wherein:
X is xe2x80x94CHR5xe2x80x94, xe2x80x94CHR5-alkyl-, or xe2x80x94CHR5-alkenyl-;
R2 is selected from the group consisting of:
-hydrogen;
-alkyl;
-alkenyl;
-aryl;
-heteroaryl;
-heterocyclyl;
-alkyl-Y-alkyl;
-alkyl-Y-alkenyl;
-alkyl-Y-aryl; and
-alkyl or alkenyl substituted by one or more substituents selected from the group consisting of:
xe2x80x94OH;
-halogen;
xe2x80x94N(R5)2;
xe2x80x94COxe2x80x94N(R5)2;
xe2x80x94COxe2x80x94C1-10 alkyl;
xe2x80x94COxe2x80x94Oxe2x80x94C1-10 alkyl;
xe2x80x94N3;
-aryl;
-heteroaryl;
-heterocyclyl;
xe2x80x94CO-aryl; and
xe2x80x94CO-heteroaryl;
each R4 is independently alkyl or alkenyl, which may be interrupted by one or more xe2x80x94Oxe2x80x94 groups;
R7 is H, C1-10 alkyl, or arylalkyl; or R4 and R7 can join to form a ring;
each Y is independently xe2x80x94Oxe2x80x94 or xe2x80x94S(O)0-2xe2x80x94;
n is 0 to 4; and
each R present is independently selected from the group consisting of C1-10 alkyl, C1-10 alkoxy, hydroxy, halogen and trifluoromethyl;
or a pharmaceutically acceptable salt thereof.
As used herein, the terms xe2x80x9calkylxe2x80x9d, xe2x80x9calkenylxe2x80x9d and the prefix xe2x80x9calk-xe2x80x9d are inclusive of both straight chain and branched chain groups and of cyclic groups, i.e. cycloalkyl and cycloalkenyl. Unless otherwise specified, these groups contain from 1 to 20 carbon atoms, with alkenyl groups containing from 2 to 20 carbon atoms. Preferred groups have a total of up to 10 carbon atoms. Cyclic groups can be monocyclic or polycyclic and preferably have from 3 to 10 ring carbon atoms. Exemplary cyclic groups include cyclopropyl, cyclopropylmethyl, cyclopentyl, cyclohexyl and adamantyl.
In addition, the alkyl and alkenyl portions of-X-groups can be unsubstituted or substituted by one or more substituents, which substituents are selected from the groups consisting of alkyl, alkenyl, aryl, heteroaryl, heterocyclyl, arylalkyl, heteroarylalkyl, and heterocyclylalkyl.
The term xe2x80x9chaloalkylxe2x80x9d is inclusive of groups that are substituted by one or more halogen atoms, including perfluorinated groups. This is also true of groups that include the prefix xe2x80x9chalo-xe2x80x9d. Examples of suitable haloalkyl groups are chloromethyl, trifluoromethyl, and the like.
The term xe2x80x9carylxe2x80x9d as used herein includes carbocyclic aromatic rings or ring systems. Examples of aryl groups include phenyl, naphthyl, biphenyl, fluorenyl and indenyl. The term xe2x80x9cheteroarylxe2x80x9d includes aromatic rings or ring systems that contain at least one ring hetero atom (e.g., O, S, N). Suitable heteroaryl groups include furyl, thienyl, pyridyl, quinolinyl, isoquinolinyl, indolyl, isoindolyl, triazolyl, pyrrolyl, tetrazolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, benzofuranyl, benzothiophenyl, carbazolyl, benzoxazolyl, pyrimidinyl, benzimidazolyl, quinoxalinyl, benzothiazolyl, naphthyridinyl, isoxazolyl, isothiazolyl, purinyl, quinazolinyl, and so on.
xe2x80x9cHeterocyclylxe2x80x9d includes non-aromatic rings or ring systems that contain at least one ring hetero atom (e.g., O, S, N) and includes all of the fully saturated and partially unsaturated derivatives of the above mentioned heteroaryl groups. Exemplary heterocyclic groups include pyrrolidinyl, tetrahydrofuranyl, morpholinyl, thiomorpholinyl, piperidinyl, piperazinyl, thiazolidinyl, imidazolidinyl, isothiazolidinyl, and the like.
The aryl, heteroaryl, and heterocyclyl groups can be unsubstituted or substituted by one or more substituents independently selected from the group consisting of alkyl, alkoxy, alkylthio, haloalkyl, haloalkoxy, haloalkylthio, halogen, nitro, hydroxy, mercapto, cyano, carboxy, formyl, aryl, aryloxy, arylthio, arylalkoxy, arylalkylthio, heteroaryl, heteroaryloxy, heteroarylthio, heteroarylalkoxy, heteroarylalkylthio, amino, alkylamino, dialkylamino, heterocyclyl, heterocycloalkyl, alkylcarbonyl, alkenylcarbonyl, alkoxycarbonyl, haloalkylcarbonyl, haloalkoxycarbonyl, alkylthiocarbonyl, arylcarbonyl, heteroarylcarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, arylthiocarbonyl, heteroarylthiocarbonyl, alkanoyloxy, alkanoylthio, alkanoylamino, aroyloxy, aroylthio, aroylamino, alkylaminosulfonyl, alkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, aryldiazinyl, alkylsulfonylamino, arylsulfonylamino, arylalkylsulfonylamino, alkylcarbonylamino, alkenylcarbonylamino, arylcarbonylamino, arylalkylcarbonylamino, heteroarylcarbonylamino, heteroarylalkycarbonylamino, alkylsulfonylamino, alkenylsulfonylamino, arylsulfonylamino, arylalkylsulfonylamino, heteroarylsulfonylamino, heteroarylalkylsulfonylamino, alkylaminocarbonylamino, alkenylaminocarbonylamino, arylaminocarbonylamino, arylalkylaminocarbonylamino, heteroarylaminocarbonylamino, heteroarylalkylaminocarbonylamino and, in the case of heterocyclyl, oxo. If any other groups are identified as being xe2x80x9csubstitutedxe2x80x9d or xe2x80x9coptionally substitutedxe2x80x9d, then those groups can also be substituted by one or more of the above enumerated substituents.
Certain substituents are generally preferred. For example, preferred R1 groups include xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-alkyl and xe2x80x94R4xe2x80x94CR3xe2x80x94Zxe2x80x94R6-aryl, wherein the alkyl and aryl groups can be unsubstituted or substituted; R3 is preferably xe2x95x90O; R4 is preferably ethylene or n-butylene; and Z is preferably xe2x80x94NR5xe2x80x94. Preferably no R substituents are present (i.e., n is 0). Preferred R2 groups include alkyl groups having 1 to 4 carbon atoms (i.e., methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and cyclopropylmethyl), methoxyethyl, and ethoxymethyl. For substituted groups such as substituted alkyl or substituted aryl groups, preferred substituents include halogen, nitrile, methoxy, trifluoromethyl, and trifluoromethoxy. One or more of these preferred substituents, if present, can be present in the compounds of the invention in any combination.
The invention is inclusive of the compounds described herein in any of their pharmaceutically acceptable forms, including isomers (e.g., diastereomers and enantiomers), salts, solvates, polymorphs, and the like. In particular, if a compound is optically active, the invention specifically includes each of the compound""s enantiomers as well as racemic mixtures of the enantiomers.
Pharmaceutical Compositions and Biological Activity
Pharmaceutical compositions of the invention contain a therapeutically effective amount of a compound of the invention as described above in combination with a pharmaceutically acceptable carrier.
The term xe2x80x9ca therapeutically effective amountxe2x80x9d means an amount of the compound sufficient to induce a therapeutic effect, such as cytokine induction, antitumor activity, and/or antiviral activity. Although the exact amount of active compound used in a pharmaceutical composition of the invention will vary according to factors known to those of skill in the art, such as the physical and chemical nature of the compound, the nature of the carrier, and the intended dosing regimen, it is anticipated that the compositions of the invention will contain sufficient active ingredient to provide a dose of about 100 ng/kg to about 50 mg/kg, preferably about 10 xcexcg/kg to about 5 mg/kg, of the compound to the subject. Any of the conventional dosage forms may be used, such as tablets, lozenges, parenteral formulations, syrups, creams, ointments, aerosol formulations, transdermal patches, transmucosal patches and the like.
The compounds of the invention can be administered as the single therapeutic agent in the treatment regimen, or the compounds of the invention may be administered in combination with one another or with other active agents, including additional immune response modifiers, antivirals, antibiotics, etc.
The compounds of the invention have been shown to induce the production of certain cytokines in experiments performed according to the tests set forth below. These results indicate that the compounds are useful as immune response modifiers that can modulate the immune response in a number of different ways, rendering them useful in the treatment of a variety of disorders.
Cytokines whose production may be induced by the administration of compounds according to the invention generally include interferon-xcex1 (IFN-xcex1) and/or tumor necrosis factor-cc (TNF-xcex1) as well as certain interleukins (IL). Cytokines whose biosynthesis may be induced by compounds of the invention include IFN-xcex1, TNF-xcex1, IL-1, IL-6, IL-10 and IL-12, and a variety of other cytokines. Among other effects, these and other cytokines can inhibit virus production and tumor cell growth, making the compounds useful in the treatment of viral diseases and tumors. Accordingly, the invention provides a method of inducing cytokine biosynthesis in an animal comprising administering an effective amount of a compound or composition of the invention to the animal.
Certain compounds of the invention have been found to preferentially induce the expression of IFN-xcex1 in a population of hematopoietic cells such as PBMCs (peripheral blood mononuclear cells) containing pDC2 cells (precursor dendritic cell-type 2) without concomitant production of significant levels of inflammatory cytokines.
In addition to the ability to induce the production of cytokines, the compounds of the invention affect other aspects of the innate immune response. For example, natural killer cell activity may be stimulated, an effect that may be due to cytokine induction. The compounds may also activate macrophages, which in turn stimulates secretion of nitric oxide and the production of additional cytokines. Further, the compounds may cause proliferation and differentiation of B-lymphocytes.
Compounds of the invention also have an effect on the acquired immune response. For example, although there is not believed to be any direct effect on T cells or direct induction of T cell cytokines, the production of the T helper type 1 (Th1) cytokine IFN-xcex3 is induced indirectly and the production of the T helper type 2 (Th2) cytokines IL-4, IL-5 and IL-13 are inhibited upon administration of the compounds. This activity means that the compounds are useful in the treatment of diseases where upregulation of the Th1 response and/or downregulation of the Th2 response is desired. In view of the ability of compounds of the invention to inhibit the Th2 immune response, the compounds are expected to be useful in the treatment of atopic diseases, e.g., atopic dermatitis, asthma, allergy, allergic rhinitis; systemic lupus erythematosis; as a vaccine adjuvant for cell mediated immunity; and possibly as a treatment for recurrent fungal diseases and chlamydia.
The immune response modifying effects of the compounds make them useful in the treatment of a wide variety of conditions. Because of their ability to induce the production of cytokines such as IFN-xcex1 and/or TNF-xcex1, the compounds are particularly useful in the treatment of viral diseases and tumors. This immunomodulating activity suggests that compounds of the invention are useful in treating diseases such as, but not limited to, viral diseases including genital warts; common warts; plantar warts; Hepatitis B; Hepatitis C; Herpes Simplex Virus Type I and Type II; molluscum contagiosum; varriola major; HIV; CMV; VZV; rhinovirus; adenovirus; influenza; and para-influenza; intraepithelial neoplasias such as cervical intraepithelial neoplasia; human papillomavirus (HPV) and associated neoplasias; fungal diseases, e.g. candida, aspergillus, and cryptococcal meningitis; neoplastic diseases, e.g., basal cell carcinoma, hairy cell leukemia, Kaposi""s sarcoma, renal cell carcinoma, squamous cell carcinoma, myelogenous leukemia, multiple myeloma, melanoma, non-Hodgkin""s lymphoma, cutaneous T-cell lymphoma, and other cancers; parasitic diseases, e.g. pneumocystis carnii, cryptosporidiosis, histoplasmosis, toxoplasmosis, trypanosome infection, and leishmaniasis; and bacterial infections, e.g., tuberculosis, and mycobacterium avium. Additional diseases or conditions that can be treated using the compounds of the invention include actinic keratosis; eczema; eosinophilia; essential thrombocythaemia; leprosy; multiple sclerosis; Ommen""s syndrome; discoid lupus; Bowen""s disease; Bowenoid papulosis; alopecia areata; the inhibition of Keloid formation after surgery and other types of post-surgical scars. In addition, these compounds could enhance or stimulate the healing of wounds, including chronic wounds. The compounds may be useful for treating the opportunistic infections and tumors that occur after suppression of cell mediated immunity in, for example, transplant patients, cancer patients and HIV patients.
An amount of a compound effective to induce cytokine biosynthesis is an amount sufficient to cause one or more cell types, such as monocytes, macrophages, dendritic cells and B-cells to produce an amount of one or more cytokines such as, for example, IFN-xcex1, TNF-xcex1, IL-1, IL-6, IL-10 and IL-12 that is increased over the background level of such cytokines. The precise amount will vary according to factors known in the art but is expected to be a dose of about 100 ng/kg to about 50 mg/kg, preferably about 10 xcexcg/kg to about 5 mg/kg. The invention also provides a method of treating a viral infection in an animal and a method of treating a neoplastic disease in an animal comprising administering an effective amount of a compound or composition of the invention to the animal. An amount effective to treat or inhibit a viral infection is an amount that will cause a reduction in one or more of the manifestations of viral infection, such as viral lesions, viral load, rate of virus production, and mortality as compared to untreated control animals. The precise amount will vary according to factors known in the art but is expected to be a dose of about 100 ng/kg to about 50 mg/kg, preferably about 10 xcexcg/kg to about 5 mg/kg. An amount of a compound effective to treat a neoplastic condition is an amount that will cause a reduction in tumor size or in the number of tumor foci. Again, the precise amount will vary according to factors known in the art but is expected to be a dose of about 100 ng/kg to about 50 mg/kg, preferably about 10 xcexcg/kg to about 5 mg/kg.
The invention is further described by the following examples, which are provided for illustration only and are not intended to be limiting in any way.
In the examples below some of the compounds were purified using semi-preparative HPLC. Two different methods were used and they are described below.
Method A
This method used a A-100 Gilson-6 equipped with 900 Series Intelligent Interface. The semi-prep HPLC fractions were analyzed by LC-APCI/MS and the appropriate fractions were combined and lyophilized to provide the trifluoroacetate salt of the desired compound.
Column: column Microsorb C18, 21.4xc3x97250 mm, 8 micron particle size, 60 xc3x85 pore; flow rate: 10 mL/min.; gradient elution from 2-95% B in 25 min., hold at 95% B for 5 min., where A=0.1% trifluoroacetic acid/water and B=0. 1% trifluoroacetic acid/acetonitrile; peak detection at 254 nm for triggering fraction collection.
Method B
This method used a Waters Fraction Lynx automated purification system. The semi-prep HPLC fractions were analyzed using a Micromass LC-TOFMS and the appropriate fractions were combined and centrifuge evaporated to provide the trifluoroacetate salt of the desired compound. The structure was confirmed by 1H NMR spectroscopy.
Column: Phenomenex Luna C18(2), 10xc3x9750 mm, 5 micron particle size, 100 xc3x85 pore; flow rate: 25 mL/min.; gradient elution from 5-65% B in 4 min., then 65 to 95% B in 0.1 min, then hold at 95% B for 0.4 min., where A=0.05% trifluoroacetic acid/water and B=0.05% trifluoroacetic acid/acetonitrile; fraction collection by mass-selective triggering.